1. Field of the Invention
The present invention relates to physical exercise apparatus for use in developing human muscles.
2. Description of the Prior Art
The human body has a substantial number of muscle groups and in the past various types of mechanical exercise equipment have been used to increase both muscular strength and size. However, prior exercise devices have either been relatively complex or limited in versatility and efficiency in terms of the number of muscle groups that individual apparatus could adequately develop.
Physiological studies have shown that in most cases power output or strength exerted by the human limbs or trunk actually varies in intensity throughout the normal range of motion of these body parts, due to the unique interaction of muscular strength curves and skeletal leverage.
Therefore, throughout the range of an exercise movement, resistance should, in most cases, match the power output of the contracting muscle or muscles.
Designers of prior exercise equipment have failed to recognize this principle and have provided resistance curves, inadequate in terms of generating maximum contraction of muscle fiber throughout the entire range of an exercise movement.
Currently available exercise equipment which provides changing resistance curves throughout a range of movement generally employ cams or levers or complex combinations of such components, but which generally cannot be altered by the user. Additionally, the geometry of the cams or gears is such that each set of such components is designed for the exercise of a specific muscle group and therefore separate machines must be provided for the exercise of each individual muscle group. The user of such equipment may be able to alter the weight supplied or resistance however this would merely provide a parallel shift in the resistance curve. Generally, there is not provided in the existing exercise equipment a means for altering the resistance curves to accomodate different muscle groups, and thus permit a number of muscle groups to be adequately trained on a single exercise apparatus.